1. Field of the Invention
The present invention relates to a constructional laser including a housing with a light source located inside the housing for emitting a visible laser beam rotatable about a rotational axis, a base plate attached to the housing and provided with an inner thread approximately in a center of the base plate, and two handles for lifting and carrying the laser and connected to the base plate.
2. Description of the Prior Art
Lasers are used in constructional industry, in plumbing and electrical trade and related fields, as an auxiliary means for laying down horizontal or vertical liners on ceilings, walls and floors or for setting horizontal or vertical planes in a space. E.g., they are necessary for the alignment of door cases and windows and for determining an exact horizontal or vertical course of electrical lines. The constructional lasers are also used for the horizontal or vertical arrangement of attachment points.
A constructional laser includes a laser which is located in the housing and emitted beam of which is rotated for producing a line. For setting a plane in a room or a space, two laser beams, which are set to each other at a right angle, are used. The rotation of the laser beams is achieved either by the rotation of the laser or the rotation of a laser beam deflection device. The commercially available laser with a rotatable laser beam permits to obtain a horizontal marking on walls when the base plate of the laser housing is oriented toward the floor. A horizontal arrangement of the laser beam is sufficient for many applications. The exact alignment of the laser beam is effected with adjustment screws provided on the laser housing and which permit to tilt the rotational axis of the laser beam. In order to be able to lay down horizontal markings at a different height, the laser housing can be mounted on a tripod. To this end, the base plate of the laser housing is usually provided with an inner thread into which an attachment screw, which is provided on the tripod, can be screwed in. In order to secure the constructional laser on the tripod, the housing should be lifted with two hands, positioned on the mounting plate of the tripod and secured. Usually, for mounting of a constructional laser, two persons are necessary, with one person taking care of preventing the apparatus from falling down while the other person screws the tripod attachment screw into the base plate. To facilitate carrying of the apparatus, constructional lasers, which have a handle on the upper surface of the laser, are available. The handle permits to lift the laser with one hand. In this way, one person can mount the laser on a tripod. However, providing a handle on the upper surface of the laser housing makes mounting of the laser at a greater height more difficult.
It is often necessary to lay down vertical lines and planes. To this end, a commercially available constructional laser, which is designed for laying down horizontal lines and planes, should be pivoted by 90.degree. relative to its conventionally used position. For a conventional laser of this type, to this end, a separate angular holding device is provided, which is attachable to the housing. The attachment of the holding device is effected by screwing-in of an attachment screw into an inner thread which is provided in the base plate of the housing for attachment of a tripod. The housing then is adjusted on a approximately rectangular support plate which projects from the holding device at a right angle. To mount the laser on a tripod, the holding device should be detached from the base plate to free the attachment inner thread of the base plate so that the tripod attachment screw can be screwed in.
The support plate, which extends at a right angle to the holding device, has three servo positioners located at three corners, providing a three-point support. The fourth corner of the support plate does not have any support. At least one of the servo-positioners is height adjustable for compensating an unevenness of the base surface. In association with the adjusting screws provided on the laser housing for tilting the rotational axis of the laser beam, this provides for vertical alignment of the laser beam. The arrangement of the servo positioners at the corners of the support plate makes the alignment of the constructional laser more difficult, because the height adjustment of the adjustable servo positioner causes tilting of the laser beam rotational axis in two planes. This tilting should again be compensated with adjusting screws provided on the laser housing. This can result in sidewise displacement of the laser beam rotational axis which, in turn, requires new positioning of the housing. Thus, the alignment process should be repeated again.
Accordingly, an object of the present invention is to provide an improved constructional laser of the above-described type which would insure a convenient handling of the apparatus. The modified constructional laser should insure laying down both horizontal lines and planes. The attachment and detachment of the holding devices for different applications should be eliminated. Further, the modified constructional laser should be convenient to carry. The modified constructional laser should require only one person for its mounting on a tripod. The alignment of the laser beam for projection vertical lines and planes in a space or zoom should be simplified.